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Accentuating the negative: Below-zero temperatures in Chicago

December 26, 2004|By Tom Skilling

Chicago is emerging from a pre-Christmas cold snap, having just experienced the first negative temperature of winter 2004-05. With city weather records dating back to late 1870, temperatures here have dropped below zero 983 times--an average of just over 7 days per year. More than 90 percent of Chicago winters have recorded at least one subzero day, and since 1870 there have only been 12 winters without one, the most recent being the winter of 1982-83 where the season's lowest reading dropped to only 3(degrees). In contrast, the winter of 1884-85 recorded 25 days with below-zero temperatures. Chicago's below-zero season begins with its earliest subzero reading, which occurred on Nov. 23 (recorded in 1950), and runs for four months until the city's latest below-zero day on March 22 (1888). The season peaks from mid-January through early February, coinciding with the time of the city's most persistent snow cover--a key factor for subzero temperatures.

Sources: Frank Wachowski, National Weather Service archives

WGN-TV/Steve Kahn

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Tom Skilling is chief meteorologist at WGN-TV. His forecasts can be seen Monday through Friday on WGN-TV News at noon and 9 p.m.